Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C11/00—Regeneration of pulp liquors or effluent waste waters
  • D21C11/0021—Introduction of various effluents, e.g. waste waters, into the pulping, recovery and regeneration cycle (closed-cycle)
  • D21C11/0028—Effluents derived from the washing or bleaching plants
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/10—Bleaching ; Apparatus therefor
  • D21C9/1005—Pretreatment of the pulp, e.g. degassing the pulp
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/10—Inorganic compounds
  • C02F2101/20—Heavy metals or heavy metal compounds
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/10—Inorganic compounds
  • C02F2101/20—Heavy metals or heavy metal compounds
  • C02F2101/203—Iron or iron compound
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/10—Inorganic compounds
  • C02F2101/20—Heavy metals or heavy metal compounds
  • C02F2101/206—Manganese or manganese compounds
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/26—Nature of the water, waste water, sewage or sludge to be treated from the processing of plants or parts thereof
  • C02F2103/28—Nature of the water, waste water, sewage or sludge to be treated from the processing of plants or parts thereof from the paper or cellulose industry
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P40/00—Technologies relating to the processing of minerals
  • Y02P40/40—Production or processing of lime, e.g. limestone regeneration of lime in pulp and sugar mills
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S210/00—Liquid purification or separation
  • Y10S210/902—Materials removed
  • Y10S210/911—Cumulative poison
  • Y10S210/912—Heavy metal
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S210/00—Liquid purification or separation
  • Y10S210/918—Miscellaneous specific techniques
  • Y10S210/919—Miscellaneous specific techniques using combined systems by merging parallel diverse waste systems
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S210/00—Liquid purification or separation
  • Y10S210/928—Paper mill waste, e.g. white water, black liquor treated

Definitions

• the parent applications show a method and apparatus for minimizing adverse environmental impact of the production of kraft pulp, or the like, by bleaching the pulp without chlorine or chlorine-containing liquids, and removing metals (such as Mn, Fe and Cu) to prevent buildup of those metals to a level adversely affecting the bleaching reactions.
• an acidic liquid stream such as washer filtrate following a bleach plant acidic stage, is treated with alkaline material containing carbonate in a reactor so that the pH is raised to a point where much of the dissolved metal in the filtrate precipitates out, and the precipitated metals are removed by optional clarification and/or filtration.
• a simple, advantageous, yet effective process and apparatus are employed for removing the chemical-consuming sulfides and increasing the carbonates so that the filtrate can be used anywhere in the pulp mill, including in the bleach plant (e.g. as a wash liquid, to manufacture bleaching chemical, etc.).
• FIGURES 6 and 7 are side schematic cross-sectional views illustrating exemplary commercial apparatus for scrubbing liquor with carbon dioxide gas, according to the present invention.
• the pulp in line 10 passes to oxygen reactor 11 where oxygen delignification takes place, and then the oxygen delignified pulp is subjected to a wash or thickening in washing or thickening stage 12, which produces a filtrate.
• stage 12 it passes to a chelating stage 13, e.g. an EDTA stage, an acid only stage, a combination EDTA-acid stage, etc.
• a chelating stage 13 e.g. an EDTA stage, an acid only stage, a combination EDTA-acid stage, etc.
• the pulp is subjected to an acidic or neutral treatment, dissolving transition metals or making them easier to remove.
• the pulp is washed or thickened as indicated at stage 14, and then passes to various bleaching stages.
• the potential Eo is increased, the insoluble Fe(OH)3 becomes more predominant or is more likely to form even at neutral or even a slightly acidic pH.
• metal precipitation is enhanced not only by increasing pH, but also by oxidation. After oxidation at 44, the metals are easier to precipitate out of the filtrate, and in fact will start precipitating even at a pH as low as 6. It is desirable to have the pH within the range of about 6-11 , preferably 8-11, to insure effective precipitation of all metals.
• carbonate ion is also preferably added in reactor 33 when the pH is adjusted to control the calcium level in the filtrate.
• the plunger type reactor 44' of FIGURE 4 may be used as oxidation means 44 of FIGURE 3.
• the designation "plunger” refers to the fact that recirculating liquid plunges into a liquid level maintained in the reactor, providing agitation which exposes the liquid to oxidizing gas maintained at a predetermined pressure above the liquid level.
• reactor vessel 62 has the inlet 32 for filtrate to be treated essentially at or below the level of liquid (filtrate) maintained in the vessel 62, and inlet 45 for oxidizing gas, adjacent the top of the vessel 62.
• Downwardly extending pipe 63 introduces recirculated liquid that "plunges" into the liquid in the vessel 62, causing agitation, and then exposure of the liquid to the oxidizing gas in atmosphere 69.
• Pipe 63 is connected by pipe 64 to pump 65, in turn connected to pipe 66 coming from the bottom of the vessel 62.
• the pump 65 essentially continuously recirculates a part of the liquid maintained in the vessel 62.
• Valve 68 in conduit 45 may be used to control the introduction of oxidizing gas.
• the valve 68 may operate in response to the pressure in the volume 69 (related to the extent to which the liquid is oxidized).
• a valve 72 may be provided to divert some liquid from line 66 to the pump 65 to be recirculated; and another part of the liquid into conduit 71 to pass to reactor 33.
• the pH may be monitored and adjusted with the addition of lime or lime mud to the reactor 62 (for substantially simultaneous oxidation and pH adjustment).
• the recovery boiler or hog-fuel boiler, or kiln) (e.g. a lime reburning kiln) 76 which already exists in the pulp mill -- is brought into contact with the alkali liquid in the gas-liquid contacting apparatus 75.
• the carbon dioxide scrubs the hydrosulfide ions from the green liquor or white liquor producing a sulfide-depleted alkali liquid which is added to the reactor 33, and is used to increase the pH of the filtrate in line 32 (which can be oxidized as indicated at box 44 in FIGURE 2) so that the ultimate filtrate produced in line 41 can be used more effectively in the bleach plant.
• the carbon dioxide has a further benefit of increasing the carbonate content of the alkali source.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Paper (AREA)
• Processing Of Solid Wastes (AREA)
• Physical Water Treatments (AREA)
• Treatment Of Water By Oxidation Or Reduction (AREA)
• Treating Waste Gases (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)
• Separation Of Suspended Particles By Flocculating Agents (AREA)

Applications Claiming Priority (7)

Publications (2)

Family

ID=27364854

Family Applications (1)

Country Status (9)

Cited By (1)

Families Citing this family (24)

Citations (3)

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• 1994
  • 1994-02-14 US US08/195,139 patent/US5509999A/en not_active Expired - Fee Related
  • 1994-03-07 CA CA002134882A patent/CA2134882A1/en not_active Abandoned
  • 1994-03-07 AT AT94910843T patent/ATE175250T1/de not_active IP Right Cessation
  • 1994-03-07 WO PCT/US1994/002373 patent/WO1994021857A1/en not_active Ceased
  • 1994-03-07 ES ES94910843T patent/ES2126103T3/es not_active Expired - Lifetime
  • 1994-03-07 EP EP94910843A patent/EP0642610B1/de not_active Expired - Lifetime
  • 1994-03-07 JP JP6521072A patent/JPH07507850A/ja active Pending
  • 1994-03-07 FI FI945514A patent/FI945514L/fi unknown
  • 1994-03-07 DE DE69415619T patent/DE69415619T2/de not_active Expired - Fee Related

Patent Citations (3)

Non-Patent Citations (2)

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